package demo;

import java.util.Scanner;

/**
 * Created with IntelliJ IDEA.
 * Description:
 * User: YKH
 * Date: 2023-03-19
 * Time: 20:49
 */
public class Main13 {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long a = sc.nextLong();
        long b = sc.nextLong();
        long n = sc.nextLong();

        long res = n/(5*a+2*b) * 7;
        n %= (5*a+2*b);
        long []arr = {a,a,a,a,a,b,b};
        for(int i=0; n>0;i++){
            n-=arr[i];
            res++;
        }
        System.out.println(res);
    }
}
